perf/core: Move perf_event sysctls into kernel/events

Move ctl tables to two files:

 - perf_event_{paranoid,mlock_kb,max_sample_rate} and
   perf_cpu_time_max_percent into kernel/events/core.c

 - perf_event_max_{stack,context_per_stack} into
   kernel/events/callchain.c

Make static variables and functions that are fully contained in core.c
and callchain.cand remove them from include/linux/perf_event.h.
Additionally six_hundred_forty_kb is moved to callchain.c.

Two new sysctl tables are added ({callchain,events_core}_sysctl_table)
with their respective sysctl registration functions.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kerenel/sysctl.c.

Signed-off-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250218-jag-mv_ctltables-v1-5-cd3698ab8d29@kernel.org

1 files changed, 32 insertions, 6 deletions

diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 8a47e52a454f..6c83ad674d01 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -22,6 +22,7 @@ struct callchain_cpus_entries {
 
 int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
 int sysctl_perf_event_max_contexts_per_stack __read_mostly = PERF_MAX_CONTEXTS_PER_STACK;
+static const int six_hundred_forty_kb = 640 * 1024;
 
 static inline size_t perf_callchain_entry__sizeof(void)
 {
@@ -266,12 +267,8 @@ exit_put:
 	return entry;
 }
 
-/*
- * Used for sysctl_perf_event_max_stack and
- * sysctl_perf_event_max_contexts_per_stack.
- */
-int perf_event_max_stack_handler(const struct ctl_table *table, int write,
-				 void *buffer, size_t *lenp, loff_t *ppos)
+static int perf_event_max_stack_handler(const struct ctl_table *table, int write,
+					void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *value = table->data;
 	int new_value = *value, ret;
@@ -292,3 +289,32 @@ int perf_event_max_stack_handler(const struct ctl_table *table, int write,
 
 	return ret;
 }
+
+static const struct ctl_table callchain_sysctl_table[] = {
+	{
+		.procname	= "perf_event_max_stack",
+		.data		= &sysctl_perf_event_max_stack,
+		.maxlen		= sizeof(sysctl_perf_event_max_stack),
+		.mode		= 0644,
+		.proc_handler	= perf_event_max_stack_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= (void *)&six_hundred_forty_kb,
+	},
+	{
+		.procname	= "perf_event_max_contexts_per_stack",
+		.data		= &sysctl_perf_event_max_contexts_per_stack,
+		.maxlen		= sizeof(sysctl_perf_event_max_contexts_per_stack),
+		.mode		= 0644,
+		.proc_handler	= perf_event_max_stack_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_THOUSAND,
+	},
+};
+
+static int __init init_callchain_sysctls(void)
+{
+	register_sysctl_init("kernel", callchain_sysctl_table);
+	return 0;
+}
+core_initcall(init_callchain_sysctls);
+